Wednesday, October 31, 2012

Cool October marks first below normal month in Winnipeg since May 2011

October 2012 temperature summary for Winnipeg

A cooler than normal October will go down as the first below normal month in Winnipeg since May 2011.. or 17 months ago. Over that time, Winnipeg has seen 16 consecutive months near or above normal including 14 straight months above normal from July 2011 to August 2012, an unprecedented stretch of warmth in Winnipeg since records began 140 years ago in 1872. October finished with a mean temperature of +4.0C, or about 1.3C below the normal October mean of 5.3C (based on 1971-2000 averages). The bigger story for October was the return of some much needed precipitation, with 57.5 mm recorded at YWG airport, about 20 mm wetter than normal for October. It was the first wetter than normal month in Winnipeg since May, and comes after an exceptionally dry September that was the second driest on record. Precipitation amounts were even greater elsewhere in the city with 72 mm at the Forks and 85 mm in Charleswood. Outside the city, the big weather story in October was the early October snowstorm on the 4th that brought up to 30 cm of heavy snow over southeast MB.

11 comments:

Looking back at the stats, I'm calling Sept 2012 "near normal" which was only 0.3C above the 1971-2000 average, as well as June 2011, which was just 0.1C above the 1971-2000 average. So the actual above normal streak was 14 straight months from July 2011 to August 2012. Regardless, October was our first month below normal since May 2011, almost a year and a half ago.

It seems EC over the last 2-3week has been forecasting sunny days 2 to five days out every day and then when the day comes it ends up being a grey and rainy/drizly day basically every day. Any reason the 2 day out is always so wrong. Sounds like Fridays forecast is going to be wrong again as well.

Daryl..Forecasts after Day 2 are completely automated from computer output, with no human input. So those forecasts are at the mercy of the model that drives them. In the fall, the models can be particularly poor with predicting low level clouds and precipitation as cooler air moves over still open lakes. Meteorologists know these situations and can modify the forecasts to reflect this, but only on Days 1 and 2. After that, the forecast is totally automated with no human input. So take those forecasts with a grain of salt..

As for Friday, I'm puzzled why there is no snow mentioned in the forecast, since most models show snow moving in by afternoon in Winnipeg, even the GLB which drives EC's extended range forecast. It looks like we could see a few cm of snow starting Friday afternoon and continuing into the evening..

Models keep bulk of snowfall over SW MB where 5-10 cm is possible overnight into Friday, before main swath weakens and slides to our southwest. Nonetheless, we still should see some snow developing here in Winnipeg by the afternoon into the evening, with a couple cm possible.. a little more to our southwest.

So ensemble approach would suggest about 3-4 cm for Winnipeg beginning sometime Friday afternoon and ending early Saturday morning. Models agree that bulk of the snow with this system will occur over SW MB and southwest of Winnipeg where 5-10 cm is possible.

Check out Edmonton, looking like a winter wonderland and the river is already starting to freeze up due to consistent below zero daytime highs for almost 2 weeks now. http://easweb.eas.ualberta.ca/camera/camera_high_01.jpgCertainly quite a different reality out west compared to here these days.

That's what I suspected.. Not the right thing to translate airport normals to the Forks given its urban micro-climate, but hm I guess Winnipeg is poorly-understood by anybody outside of it no matter their background lol..